1. Field of the Invention
The present invention relates to a radiation imaging apparatus detecting radiation, such as X-rays, a radiation imaging system, and a method for manufacturing a radiation imaging apparatus, and more particularly relates to a radiation imaging apparatus used for a medical diagnostic imaging apparatus, a nondestructive inspection apparatus, an analysis apparatus, and the like.
2. Description of the Related Art
A single crystal semiconductor wafer which is generally commercially available is small as compared to a glass substrate. Therefore, in order to form a large-area radiation imaging apparatus using a single crystal semiconductor wafer, single crystal semiconductor wafers in each of which detection elements are formed are divided to form a plurality of imaging element chips, and a certain number of imaging element chips are arranged to have a desired area.
US Patent Application No. 2002/0038851 has disclosed that in order to reduce cost, before chip-shaped imaging elements are adhered to a base board which forms a part of an apparatus, inspection of the imaging elements and replacement of an imaging element having a defect discovered thereby are performed. In addition, it has been disclosed that after the inspection and the replacement are performed, the imaging elements are fixed to the base board by adhesion. Furthermore, it has also been disclosed that a scintillator which converts radiation into light having a wavelength band detectable by the imaging elements is arranged by adhesion on the imaging elements at a side opposite to the base board (substrate).
International Publication No. WO 2008/072462 has disclosed that in order to perform rework of a liquid crystal display device, a double-sided adhesive sheet which includes at least one heat peelable adhesive layer containing thermally expandable particles is used to fix a liquid crystal display module unit and a backlight unit.
However, according to the method disclosed in US Patent Application No. 2002/0038851, after the imaging elements are adhered to the base board or after the imaging elements and the scintillator are adhered to each other, it is difficult to replace an imaging element or a scintillator which is detected as a defective by the inspection. For example, in a radiation detection apparatus including a plurality of imaging elements, when an imaging element having a defect is peeled away from a base board, an imaging element having no defect may be cracked by an external force applied thereto. In addition, properties of an imaging element having no defect may be degraded in some cases by a solvent used for dissolving an adhesive. Furthermore, the case will be considered in which in an inspection step performed after imaging elements are adhered to a base board, no defects are detected in the imaging elements, but some defect is detected in an inspection step performed after a scintillator is adhered to the imaging elements. In this case, since it is believed that only the scintillator has a defect, the scintillator must be peeled away from the imaging elements and be replaced; however, the base board is not necessarily peeled away from the imaging elements. As described above, in a radiation imaging apparatus having a laminate structure in which imaging elements are provided between a scintillator and a substrate, it may be preferable in some cases that peeling between the scintillator and the imaging elements and peeling between the substrate and the imaging elements are not simultaneously performed. When the peeling between the scintillator and the imaging elements and the peeling between the substrate and the imaging elements are simultaneously performed, the imaging elements are placed in a mechanically unstable state so as to be fixed to nothing; hence, the imaging elements may collide with something while moving during the peeling and may be cracked in some cases.
In addition, in the liquid crystal display device disclosed in International Publication No. WO 2008/072462 in which one liquid crystal display module unit and one backlight unit are fixed to each other, the peeling is simply performed just between the liquid crystal display module unit and the backlight unit. That is, peeling performed in a multilayered structure including at least three layers is not taken into consideration.